Effector and Regulatory Activities of HLA-E-restricted HIV-specific abCD8 T Cells

说明书(申请人提供)：HL A-E是一种普遍表达的非经典Ib类分子。在动态平衡条件下，人类白细胞抗原-E优先向天然的CD94/NKG2受体递送经典Ia类蛋白(人类白细胞抗原-A、-B和-C)基本不变的信号肽，从而调节NK细胞活性。人类白细胞抗原E限制性调节性CD8+T细胞可能阻止自身免疫。有趣的是，对于某些细菌和病毒的感染，人类白细胞抗原-E显示了一系列由CD8+T细胞的TCR感受到的病原体来源的多肽。我们报道了第一个人类白细胞抗原E限制性HIV Gag表位(KL9)，它是通过体外再次刺激精英控制者的CD8+T细胞而确定的。对HLAE限制性KL9特异性T细胞的功能分析揭示了效应(脱颗粒)和调节功能(IL-26的产生)。这项工作将开始剖析这种尚未确定的宿主免疫，特别是绘制保守的表位图，并评估HIV感染中基于HLA-E的抗原呈递系统中这些反应的特征。这项工作对艾滋病毒疫苗的开发很重要，因为病毒可能利用了这一机制来限制宿主免疫。在人类白细胞抗原-E的背景下，效应免疫和调节免疫之间的平衡可能允许部分清除艾滋病毒，从而提供一定程度的保护，同时避免过度炎症和病理，尽管代价是病毒的持久性和慢性感染。了解嵌入的人类白细胞抗原E限制性表位如何影响HIV免疫的诱导，对于疫苗设计至关重要。与受高度多态的Ia类基因座限制的表位不同，人类白细胞抗原E多态的缺乏进一步暗示了一些与人类白细胞抗原E结合的表位可能成为通用HIV疫苗的候选表位。特定目标1将使用已建立的方案，将来自精英控制器的CD8+T细胞与HIV蛋白质组中的保守区域中的HLA-E限制性表位进行映射。表位将通过质谱学进行验证。由于人类白细胞抗原E的TCR结合面基本上是“单态的”，因此，结合的多肽强烈影响特异性和功能，因此，单个HIV表位有望引起不同的CD8+反应。《特定目标2》将研究人类白细胞抗原E限制的CD8+T细胞的效应器和调节功能，以及对新映射的特异性的公共TCR使用。三种T细胞培养将分别由精英控制员或健康捐赠者偶然产生 已绘制表位图。公共TCR的选择可能表明很大一部分人类群体能够产生反应，这些结构可以被TCR亲和力成熟等新技术利用来创造新的治疗药物类别。具体目标3将是对30名对照组和40名非抗逆转录病毒治疗的进展期患者进行的人类白细胞抗原E限制性HIV特异性CD8+T细胞的相关性研究。这些人类白细胞抗原E表位与NKG2受体相互作用的能力也将在10名HIV血清阳性个体中用人类白细胞抗原E四聚体进行评估。这些研究将为人类白细胞抗原E限制的NK和CD8+T细胞在HIV感染中的作用提供深入的认识。

DESCRIPTION (provided by applicant): HLA-E is a ubiquitously expressed non-classical class Ib molecule. Under homeostatic conditions, HLA-E preferentially presents essentially invariant signal peptides of classical class Ia proteins (HLA-A, -B, and -C) to the innate CD94/NKG2 receptors, thereby regulating NK cell activity. HLA-E-restricted regulatory CD8+ T cells may prevent autoimmunity. Of interest, with infections by certain bacteria and viruses, HLA-E displays a remarkably diverse repertoire of pathogen-derived peptides that are sensed by ¿¿ TCR of CD8+ T cells. We report the first HLA-E-restricted HIV Gag epitope (KL9) identified using in vitro-re-stimulated CD8+ T cells from an elite controller. Functional analysis f HLA-E-restricted KL9-specific T cells revealed both effector (degranulation) and regulatory functions (IL-26 production). This work will begin to dissect this yet undefined host immune immunity, particularly to map conserved epitopes and assess the character of these reactivities within the HLA-E based antigen presentation system in HIV infection. This work is important for HIV vaccine development because the virus may have co-opted this mechanism to limit host immunity. A balance between effector and regulatory immunity in the context of HLA-E might allow partial clearance of HIV, thus providing some levels of protection while avoiding excessive inflammation and pathology, albeit at the cost of viral persistence and chronic infection. Understanding how embedded HLA-E-restricted epitopes affect the induction of HIV immunity would be crucial for vaccine design. The lack of HLA-E polymorphism further implies that some HLA-E-bound epitopes may be potential candidates for a universal HIV vaccine, in contrast with those restricted by the highly polymorphic class Ia loci. Specific Aim 1 will map HLA-E-restricted epitopes in conserved domains across the HIV proteome with CD8+ T cells from elite controllers using an established protocol. Epitopes will be verified by mass spectrometry. Individual HIV epitopes are expected to elicit qualitatively distinct CD8+ responses, since the TCR-binding face of HLA-E is basically "monomorphic" and thus, the bound peptide strongly influences specificity and functions. Specific Aim 2 will examine the effector and regulatory functional profiles and public TCR usage of HLA-E-restricted CD8+ T cells to the newly mapped specificities. Three T cell cultures will be generated from elite controllers or contingently from healthy donors for each epitope mapped. Selection of public TCRs may indicate that a large segment of the human population is capable of responding and these structures can be exploited by new technologies such as TCR affinity maturation to create new classes of therapeutic agents. Specific Aim 3 will be a correlative study of HLA-E-restricted HIV-specific CD8+ T cells in 30 controllers and 40 progressor patients who are off ART. The ability of these HLA-E epitopes to interact with NKG2 receptors will also be assessed with HLA-E tetramers in 10 HIV seropositive individuals. These studies will provide insights into the role of HLA-E-restricted NK and CD8+ T cell surveillance in HIV infection.